WASHINGTON -- Telling Congress that the Obama administration took trust out of the equation by coining the new term "test but verify," Secretary of State John Kerry displayed a testy attitude with House Democrats today in trying to beat back any legislative effort to pass new sanctions against Iran.

Kerry also admitted that Tehran was essentially right when it said, despite administration claims to the contrary after the Geneva deal was inked, that it didn't lose the right to enrich uranium.

"We've heard the administration say that Iran has no right to enrich. But the Iranians this week say they do. And the joint action plan indicates that the U.S. would accept an Iranian enrichment program," House Foreign Affairs Committee chairman Ed Royce (R-Calif.) said at the hearing.

"Iran, from our standpoint, does not need this technology to generate electricity. Clearly, we're prepared to allow them to import nuclear fuel, but if they have this technology, it is exactly what they do need to make a nuclear weapon," Royce continued. "So, am I reading this right? Is the administration's position that while it may not recognize Iran's right to enrich, Iran will in practice retain an enrichment program as part of the final agreement? That is the question."

"It depends, Mr. Chairman, on the final agreement. It is not locked in, no," Kerry replied, adding that he had "one, two, three, four 'mutually agreed' or 'agreed upons'" in the Geneva pact.

"Now, those are going to have to be agreed upon, and if they can't be, no, they won't have one. If it's so limited and so verifiable and so transparent and so accountable, and you have all of the attributes of cradle-to-grave documentation," then Iran would beable to enrich uranium, he said.

"…I will say as I said to Foreign Minister Zarif in our negotiations, there is no right to enrich in the NPT, but neither is it denied."

Kerry did not submit a formal opening statement, and extemporaneously droned on for so long that Royce had to interject and ask him to wrap it up.

He vigorously defended the agreement's sanctions relief -- "we have red-teamed and vetted and cross-examined and run through all the possible numbers through the intel community" to come at the estimate of $7 billion that Iran could reap from the deal -- and brushed off Israel's concern about the deal as Washington knowing what's in Jerusalem's best interest.

What really got Kerry defensive and belligerent was not committee Republicans but the panel's Democrats -- most of whom voiced deep-seated reservations to outright opposition to the deal.

His tone, body language and continually evolving laundry list of reasons why Congress shouldn't pass any new sanctions legislation made clear just how much the administration fears potential passage of a bill with a veto-proof majority.

And that goes for any sanctions -- even ones that don't go into effect for six months, as Senate Foreign Relations Committee Chairman Robert Menendez (D-N.J.) has suggested, or those triggered by Iran reneging on the deal.

Ranking Member Eliot Engel (D-N.Y.) told Kerry that "at a minimum" the deal "should have required Iran to suspend uranium enrichment as demanded by six separate U.N. Security Council resolutions."

"I don't think it's asking too much of Iran to say that at least while we're talking, you stop enriching," he said. "…If Iran retains any enrichment capacity, how can we be sure that they will not forever remain on the brink of a breakout capacity?"

Engel also noted that our closest regional allies -- who have the most to lose because of their proximity to Iran -- were not only caught off guard by the deal but have expressed serious reservations.

"Prime Minister Netanyahu of Israel obviously had a difference tactically. The prime minister thought we should ratchet up the sanctions and keep the pressure on and somehow they would collapse," Kerry said. "We didn't read it the same way. We also felt that if I just tried to go into the negotiation for the final status comprehensive agreement, you would be allowing them to continue to grow their program while you were negotiating. And that's more like the North Korean model. You know, you sort of get into this long, prolonged negotiation, but they're progressing while you're doing it."

Engel took issue with the administration broadly opposing any new sanctions by claiming that lawmakers "would cause irreversible damage to our diplomatic process with Iran."

"If that's true, then, how can the United States send a message to Iran that there will be dire consequences if the interim deal does not come to fruition?" he said.

"I can assure you they've listened to us in every conversation that we've had, and in every conversation that our friends have had with them," Kerry said. "They know we're serious. They know the president is serious. They know we're serious about diplomacy, because we prefer to resolve this through diplomacy and to reach a reasonable accord."

"You know, when Nixon opened China and Kissinger went over and sat with Mao Zedong it wasn't based on trust, they set up a process and they began to, you know, build a different relationship. Same thing with Gorbachev and Reagan and the Soviet Union. It wasn't based on trust, it was based on a process that was put in place. So we're approaching this I think realistically …they know that if this fails, sanctions will be increased. We've said it a hundred times. And you all have said it a hundred times. And they know you're yearning to go do it."

When Engel suggested that tough sanctions could "strengthen the hand" of the administration in negotiations, Kerry snapped, "Well, I appreciate you thinking that. I'm respectfully suggesting to you that we think our hand is very, very strong and nothing is undone in the sanctions regime."

Kerry practically begged Congress not to pass sanctions. "You don't need do it," he said. "It is actually gratuitous in the context of this situation. Because you can do it in a week. If you need to. When we say this ain't working, we need your help, and believe me, we'll be prepared to do that. And you'll be partners in this as we go along, because we'll be sharing, you know, a sense of where we are and what's going on."

But Rep. Brad Sherman (D-Calif.) countered that the claim sanctions could be turned around in a week is way off.

Sherman noted that even with years of difficulty in getting the administration to support sanctions, "now you're here saying don't do anything now because we'll be with you in urging sanctions if this deal doesn't go forward."

The congressman said he was "impressed a little bit less" after reading the Geneva deal, particularly when coupled with Kerry's claim that it "halts and rolls back the program."

"The fact is, they've got 9,000 centrifuges turning now and they'll turn throughout -- they'll spin throughout the term of this agreement. So the centrifuges are literally rolling forward. You've told us that they can't increase their stockpile of enriched uranium. Yes, they can. They just have to convert it to uranium oxide," Sherman said, highlighting how the Wisconsin Project on Nuclear Arms Control calculated that Iran will, over the course of the agreement, "create enough enriched uranium for four nuclear bombs."

"Now, the one issue before Congress is whether we should adopt sanctions that go into effect in this summer, or instead that it's safe to wait. As you point out, we can pass sanctions in a week if you're lobbying for them. But if you're, as every administration has, trying to prevent them, you're asking us to be asleep and do nothing while 9,000 centrifuges turn and a new uranium stockpile is created," Sherman added, noting that the Geneva agreement's timeline puts the deadline in July -- when Congress is preparing to leave for the August recess and controversial bills are competing for attention.